New taxa of Sepulcidae (Hymenoptera) from mid-Cretaceous Kachin amber

Three new species of the genus Prosyntexis Sharkey, 1990 in the extinct sawfly family Sepulcidae, Prosyntexis aristovi sp. nov., P. lata sp. nov. and P. antennata sp. nov., are described from five well-preserved specimens from the mid-Cretaceous Kachin amber. These new species, the first records of the family Sepulcidae in Kachin amber, are placed in Prosyntexis (Trematothoracinae) based on the mesonotum membranous centrally with sides ridge transversely; forewing with the basally arched M+Cu; basal third or half of costal space narrowed; and 2r-m absent. The conspecific male and female of Prosyntexis lata with well-preserved genitalia are reported for the first time in the family Sepulcidae. A key to fossil species of Prosyntexis is provided. These new findings improve our understanding of Prosyntexis by adding more morphological features, such as antenna with no fewer than 16 segments, basal and distal hamuli present, tibia apical spurs 1-2-2, etc. The new taxa suggest that the Sepulcidae should range in age from at least from the Middle Jurassic to the mid-Cretaceous.